A comma is used to add clarity to a sentence and to enable a reader to understand the relation of its parts more quickly.
Commas: Part One
Commas in a Series
Use a comma after all but the last element in a series.
A series consists of three or more words, phrases, or clauses. When one
or more of the elements contain a comma, semicolons instead of commas are used to separate the elements.
No commas are used in a series if all of the items are joined by and, or, or nor.
Use commas after the words first, second, and so on, when these words introduce items in a series.(Note the use of semicolons n the example).
or more of the elements contain a comma, semicolons instead of commas are used to separate the elements.
- The Japanese syllabic, the Chinese logographic, and the Korean alphabetic writing systems are similar in appearance.
- The Chinese language is pronounced differently in many provinces of the country, in Taiwan, and in Hong Kong.
- Some people believe that Japanese is difficult to pronounce, that its alphabet is complicated to write, and that learning the language takes many years of study.
No commas are used in a series if all of the items are joined by and, or, or nor.
- The icy wind soon numbed the climber's face and feet and hands.
Use commas after the words first, second, and so on, when these words introduce items in a series.(Note the use of semicolons n the example).
- The word aborigine refers to three groups of people: first, an ancient mythical people; second, the aboriginal tribes of Australia; and third, any original inhabitants of a country.
Commas between Coordinate Adjectives
Coordinate adjectives are adjectives of equal rank. To determine whether adjectives are coordinate, try placing and between them. If and sounds natural, and if you can reverse the order of the adjectives without changing the meaning, then a comma is needed.
reversing their order. Therefore, a comma is needed).
necessary.)
Do not use a comma before the final adjective in a series if the adjective is thought of as part of the noun.
(American flag is considered one item, Colorful and shimmering modify American flag, not just flag. Thus, there is no comma
between shimmering and American.
If one word in a series modifies another word in the same series, no comma separates them.
Incorrect A dark, brown coat was left in the closet.
Correct A dark brown coat was left in the closet.
(Dark modifies brown, telling what shade of brown. It does not modify the noun coat.)
In general, no comma is needed after numbers and after adjectives of size, shape, and age.
a old Italian custom five small round windows.
- The cold, exhausted climbers returned to their camp.
reversing their order. Therefore, a comma is needed).
- Many animals grow a thick winter coat.
necessary.)
Do not use a comma before the final adjective in a series if the adjective is thought of as part of the noun.
- As the horns blared, the marchers formed a colorful, shimmering American flag.
(American flag is considered one item, Colorful and shimmering modify American flag, not just flag. Thus, there is no comma
between shimmering and American.
If one word in a series modifies another word in the same series, no comma separates them.
Incorrect A dark, brown coat was left in the closet.
Correct A dark brown coat was left in the closet.
(Dark modifies brown, telling what shade of brown. It does not modify the noun coat.)
In general, no comma is needed after numbers and after adjectives of size, shape, and age.
a old Italian custom five small round windows.
Commas with Introductory Elements
Use a comma after introductory words, mild interjections, or adverbs at the beginning of a sentence.
Use a comma after a series of prepositional phrases at the beginning of a sentence.
A single prepositional phrase at the beginning of the sentence need not be followed by a comma unless the comma is needed for clarity.
Use a comma after introductory infinitive phrases and introductory participial phrases used as modifiers.
Use a comma after adverbial clauses at the beginning of a sentence.
Use a comma after words of phrases that have been moved to the beginning of a sentence from their usual position.
- Well, the meeting is about to start
- Wait, I think I can access this encoded computer file.
- However, the suspect refused to answer Holmes's question.
Use a comma after a series of prepositional phrases at the beginning of a sentence.
- From his seat in the senate, the emperor Augustus listened intently.
- Under the table by the fireplace, our puppy curled up for a nap.
A single prepositional phrase at the beginning of the sentence need not be followed by a comma unless the comma is needed for clarity.
- On Saturday I work until noon.
- Before the recent hit, Wicked was the group's best production.
Use a comma after introductory infinitive phrases and introductory participial phrases used as modifiers.
- To activate the system, pull the toggle switch.
- Erupting violently, Mt. St. Helen's spewed volcanic ash for miles.
Use a comma after adverbial clauses at the beginning of a sentence.
- Although asparagus is used as a vegetable, it is actually a member of the lily family.
- Since Marla visited the museum, she has been interested in Asian art.
Use a comma after words of phrases that have been moved to the beginning of a sentence from their usual position.
- The crime was apparently committed at midnight. (usual order)
- Apparently, the crime was committed at midnight. (transposed order)
Introductory Words and Phrases | |
File Size: | 13 kb |
File Type: | docx |
Commas with Interrupters
Use a comma to set off nonessential appositives.
A nonessential appositive is a word or phrase that adds additional information to a sentence that is already clear and complete.
Use commas to set off words of direct address.
Use commas to set off parenthetical expressions.
A parenthetical expression is a word or phrase inserted in a sentence as a comment or an exclamation. The sentence is complete without it, and it should always be set off with commas. The following expressions are often used parenthetically.
A nonessential appositive is a word or phrase that adds additional information to a sentence that is already clear and complete.
- Mercury, a heavy metal, is also known as quicksilver.
- San Angel, a suburb of Mexico City, hosts a colorful craft market on Saturday.
- The opera La Traviata was written by the Italian composer Giuseppe Verdi.
- The pop sculptor George Segal is best known for his plaster casts of people.
Use commas to set off words of direct address.
- Carol, will you be the producer and director this year's holiday talent show?
- The ghost or Castle Hargrove, my gullible friend, is nothing more than the fancy of an overactive imagination.
Use commas to set off parenthetical expressions.
A parenthetical expression is a word or phrase inserted in a sentence as a comment or an exclamation. The sentence is complete without it, and it should always be set off with commas. The following expressions are often used parenthetically.
after all
by the way for instance |
of course
as a matter of fact for example |
on the other hand
I believe (hope, suggest) however (when it does not form a compound sentence) |
- The train, after all, is over an hour late.
When these words and phrases are used as basic parts of the sentence, they are not set off by commas.
- The train was late after all our rushing to be on time.
When adverbs such as however, therefore, and consequently are used parenthetically in a sentence, they are set off with commas.
- His oldest brother, however, is a much better athlete than anybody else in the Piner family.
End of Part One
Commas: Part II
Commas with Quotations
Use commas to set off a direct quotation from the rest of the sentence.
The clause that identifies the source of a quotation may appear at the beginning, in the middle, or at the end of the sentence. When it follows the quotation, the comma goes inside the quotation marks.
Do not use commas with indirect quotations.
The clause that identifies the source of a quotation may appear at the beginning, in the middle, or at the end of the sentence. When it follows the quotation, the comma goes inside the quotation marks.
- Francis said, "The Atomic Energy Commission recently sold some californium-252 for $1,000 per microgram."
- "But," said Micah, "that's about $350 billion a pound!"
- "I guess we won't be using that element in our chemistry experiment," laughed James.
Do not use commas with indirect quotations.
- Francis said that the Atomic Energy Commission had recently sold some californium-252 for $1,000 per microgram.
Commas in Compound Sentences
Use a comma before the conjunction that joins the two independent clauses of a compound sentence.
- The famous Hope diamond is said to be cursed, and many of its owners have died suddenly or mysteriously.
- Vincent Van Gogh threw away his masterpieces, but his brother Theo saved them for posterity.
- The pilot radioed the control tower and received instructions to change runways.
Commas with Nonessential Adjective Clauses
Use commas to set off nonessential adjective clauses.
A nonessential adjective clause, like a nonessential appositive phrase, supplies additional information to a sentence and can be omitted without changing the meaning of the sentence. An essential clause adds information necessary to the meaning of the sentence and is not set off by commas.
Grammar Note: In formal writing, which generally introduces nonessential clauses and that generally introduces essential clauses. Who is used when the adjective clause refers to a person and can be either essential or nonessential.
A nonessential adjective clause, like a nonessential appositive phrase, supplies additional information to a sentence and can be omitted without changing the meaning of the sentence. An essential clause adds information necessary to the meaning of the sentence and is not set off by commas.
- Nonessential Clause: Vatican City, which is an independent state, encompasses 109 acres within Rome.
- Essential Clause: The city that serves as the seat of the Roman Catholic Church is call Vatican City.
- Nonessential Clause: The painter Thomas Moran, who came to the United States from England, helped Americans see the beauty of their own country.
- Essential Clause: The painter who helped Americans recognize the need for national parks was Thomas Moran.
Grammar Note: In formal writing, which generally introduces nonessential clauses and that generally introduces essential clauses. Who is used when the adjective clause refers to a person and can be either essential or nonessential.
Commas with Nonessential Participial Phrases
Use commas to set off nonessential participial phrases.
A nonessential participial phrase adds detail to a sentence but does not change the meaning. An essential participial phrase is necessary to complete the meaning of a sentence. It is not set off by commas.
A nonessential participial phrase adds detail to a sentence but does not change the meaning. An essential participial phrase is necessary to complete the meaning of a sentence. It is not set off by commas.
- Nonessential Participial Phrase: The tourists, wishing to see a variety of European dwellings, visited both sod houses and
castles. - Essential Participial Phrase: Tourists wishing to see a variety of European dwellings can visit sod houses and castle.
(The phrase cannot be dropped.)
Commas in Dates, Places, Names, and Letters
In dates, use a comma between the day of the month and the year. When only the month and year are given, no comma is necessary.
- June 5, 1932
- September 2009
- December 17, 1903, saw the first powered flight of the Wright brothers' flying machine.
- San Antonio, Texas
- Madrid, Spain
- Sofia, Bulgaria
- Mail sent to 210 Geneva, Enid, Oklahoma 12339, will reach me.
- Managua, Nicaragua, has been the site of much suffering.
- Dear Janet,
- Your friend,
- Sincerely,
Commas with Titles and Numbers
A title following a personal name is set off with commas; business abbreviations such as Inc. or Ltd. following a company name are also set off with commas.
- Rader, Inc., has promoted Bill Stavros, CPA, to vice-president.
- The diameter of the earth is 7,927 miles.
Commas to Avoid Confusion
Use a comma to separate words or phrases that might otherwise be misread.
One source of confusion occurs when the conjunctions but and for are mistaken for prepositions.
A noun following a verb or verbal can cause confusion.
An adverb at the beginning of a sentence may be mistaken for a preposition.
Use a comma to indicate the words left out of parallel word groups
Sometimes a writer prefers not to repeat the same verb or the same subject and verb in a compound sentence; in such a sentence a comma indicates the missing element or elements.
Punctuation Note: Commas are used to add clarity to sentences. The overuse of commas can actually make sentences less clear. Add a comma only when its use is justified by the grammar and/or structure of the sentence.
One source of confusion occurs when the conjunctions but and for are mistaken for prepositions.
- Confusing: Every council representative approved the resolution for the city's historical buildings were being destroyed.
- Clear: Every council representative approved the resolution, for the city's historic buildings were begin destroyed.
A noun following a verb or verbal can cause confusion.
- Confusing: While cooking Patrick burned his hand.
- Clear: While cooking, Patrick burned his hand.
An adverb at the beginning of a sentence may be mistaken for a preposition.
- Confusing: Below the boy searched the ship's hold.
- Clear Below, the boy searched the ship's hold.
Use a comma to indicate the words left out of parallel word groups
Sometimes a writer prefers not to repeat the same verb or the same subject and verb in a compound sentence; in such a sentence a comma indicates the missing element or elements.
- The corn was tall; the wheat, golden.
- Maria's culinary specialty is dessert; Daniel's, soup.
Punctuation Note: Commas are used to add clarity to sentences. The overuse of commas can actually make sentences less clear. Add a comma only when its use is justified by the grammar and/or structure of the sentence.